MongoDB学习第七篇
一、术语和概念的对比SQLMongoDBdatabase
database
row
document or BSON document
column
field
index
index
table joins
$lookup, embedded documents primary key
Specify any unique column or column combination as primary key.
primary key
In MongoDB, the primary key is automatically set to the _id field.
aggregation (e.g. group by) aggregation pipeline
二、对库和表的操作语句对比
SQLMongoDB
CREATE TABLE people ( id MEDIUMINT NOT NULL
AUTO_INCREMENT,
user_id Varchar(30),
age Number,
status char(1),
PRIMARY KEY (id)
)
直接执行insert操作即可，如果表不存在，自动创建
db.people.insertOne( {
user_id: "abc123",
age: 55,
status: "A"
} )
也可以用一下语句创建collection
db.createCollection("people")
ALTER TABLE people
ADD join_date DATETIME
db.people.updateMany(
{ },
{ $set: { join_date: new Date() } }
)
ALTER TABLE people
DROP COLUMN join_date
db.people.updateMany(
{ },
{ $unset: { "join_date": "" } }
)
CREATE INDEX>
ON people(user_id)
db.people.createIndex( { user_id: 1 } )
CREATE INDEX idx_user_id_asc_age_desc
ON people(user_id, age DESC)
db.people.createIndex( { user_id: 1, age: -1 } )
DROP TABLE people
db.people.drop()
三、insert语句的对比
SQL INSERT StatementsMongoDB insertOne() Statements
INSERT INTO people(user_id, age,
status)
VALUES ("bcd001",
45,
"A")
db.people.insertOne( { user_id: "bcd001", age: 45, status: "A" }
)
四、select语句的对比
SQL SELECT StatementsMongoDB find() Statements
SELECT *
FROM people
db.people.find()
SELECT>user_id, status
FROM people
db.people.find(
{ },
{ user_id: 1, status: 1 }
)
SELECT user_id, status
FROM people
db.people.find(
{ },
{ user_id: 1, status: 1, _id: 0 }
)
SELECT *
FROM people
WHERE status = "A"
db.people.find(
{ status: "A" }
)
SELECT user_id, status
FROM people
WHERE status = "A"
db.people.find(
{ status: "A" },
{ user_id: 1, status: 1, _id: 0 }
)
SELECT *
FROM people
WHERE status != "A"
db.people.find(
{ status: { $ne: "A" } }
)
SELECT *
FROM people
WHERE status = "A"
AND age = 50
db.people.find(
{ status: "A",
age: 50 }
)
SELECT *
FROM people
WHERE status = "A"
OR age = 50
db.people.find(
{ $or: [ { status: "A" } ,
{ age: 50 } ] }
)
SELECT *
FROM people
WHERE age > 25
db.people.find(
{ age: { $gt: 25 } }
)
SELECT *
FROM people
WHERE age < 25
db.people.find(
{ age: { $lt: 25 } }
)
SELECT *
FROM people
WHERE age > 25
AND age <= 50
db.people.find(
{ age: { $gt: 25, $lte: 50 } }
)
SELECT *
FROM people
WHERE user_id like "%bc%"
db.people.find( { user_id: /bc/ } )
-or-
db.people.find( { user_id: { $regex: /bc/ } } )
SELECT *
FROM people
WHERE user_id like "bc%"
db.people.find( { user_id: /^bc/ } )
-or-
db.people.find( { user_id: { $regex: /^bc/ } } )
SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id ASC
db.people.find( { status: "A" } ).sort( { user_id: 1 } )
SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id DESC
db.people.find( { status: "A" } ).sort( { user_id: -1 } )
SELECT COUNT(*)
FROM people
db.people.count()
or
db.people.find().count()
SELECT COUNT(user_id)
FROM people
db.people.count( { user_id: { $exists: true } } )
or
db.people.find( { user_id: { $exists: true } } ).count()
SELECT COUNT(*)
FROM people
WHERE age > 30
db.people.count( { age: { $gt: 30 } } )
or
db.people.find( { age: { $gt: 30 } } ).count()
SELECT DISTINCT(status)
FROM people
db.people.distinct( "status" )
SELECT *
FROM people
LIMIT 1
db.people.findOne()
or
db.people.find().limit(1)
SELECT *
FROM people
LIMIT 5
SKIP 10
db.people.find().limit(5).skip(10)
EXPLAIN SELECT *
FROM people
WHERE status = "A"
db.people.find( { status: "A" } ).explain()
五、update语句的对比
SQL Update StatementsMongoDB updateMany() Statements
UPDATE people
SET status = "C"
WHERE age > 25
db.people.updateMany(
{ age: { $gt: 25 } },
{ $set: { status: "C" } }
)
UPDATE people
SET age = age + 3
WHERE status = "A"
db.people.updateMany(
{ status: "A" } ,
{ $inc: { age: 3 } }
)
六、delete语句的对比
SQL Delete StatementsMongoDB deleteMany() Statements
DELETE FROM people
WHERE status = "D"
db.people.deleteMany( { status: "D" } )
DELETE FROM people
db.people.deleteMany({})
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